According to Total Validator Cute Editor fails with these errors:

 

E007 Found '&' within 'style'. You should use '&' instead: CuteSoft_Client/CuteEditor/Load.ashx?type=theme&theme=Custom&file=all.png is all over the place and fails left and right. When I view source some of your code is properly marked up and then you have cases like this where it is not.

 

W001 There should not be any white space at the start or end of an attribute's value:

<DIV class=" CuteEditorToolbar". Throughout the loader.js there are what appears to be these unnecessary spaces.

 

E822 [WAI 3.4 (AA)] Use relative, rather than absolute units:

 

There is also a side issue of being able to set a <label for=""> in a simple manner for cute editor